Contamination of a vehicle exterior may reduce the fuel efficiency of the vehicle by increasing wind resistance of the vehicle, may interfere with the operation of various vehicle sensors, such as an outwardly directed sensor supported underneath a body panel of the vehicle, thereby leading to false error codes, may make the vehicle undesirable for a passenger such as a user of an autonomous vehicle service, etc. Often it is not possible for a vehicle to be visually inspected by a human person, and even if such an inspection is possible, it may not identify problematic contaminants. Further, vehicles lack mechanisms to detect whether a vehicle exterior is contaminated, e.g., whether the exterior has mud, road salt, etc., coating various portions of an exterior surface.